Brillouin Scattering: A Third Wave Emerges in Integrated Circuits

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Optical fibres are our global nervous system, transporting terabytes of data across the planet in the blink of an eye.

As that information travels at the speed of light across the globe, the energy of the light waves bouncing around inside the silica and polymer fibres create tiny vibrations that lead to feedback packets of sound or acoustic waves, known as ‘phonons’.

This feedback causes light to disperse, a phenomenon known as ‘Brillouin scattering’.

For most of the electronics and communications industry, this scattering of light is a nuisance, reducing the power of the signal. But for an emerging group of scientists this feedback process is being adapted to develop a new generation of integrated circuits that promise to revolutionise our 5G and broadband networks, sensors, satellite communication, radar systems, defence systems and even radio astronomy.

“It’s no exaggeration to say there is a research renaissance into this process under way,” said Professor Ben Eggleton, Director of the University of Sydney Nano Institute and co-author of a review paper published today in Nature Photonics.

“The application of this interaction between light and sound on a chip offers the opportunity for a third-wave revolution in integrated circuits.”

The microelectronics discoveries after World War II represented the first wave in integrated circuitry, which led to the ubiquity of electronic devices that rely on silicon chips, such as the mobile phone. The second wave came at the turn of this century with the development of optical electronics systems that have become the backbone of huge data centres around the world.

First electricity then light. And now the third wave is with sound waves.

Professor Eggleton is a world-leading researcher investigating how to apply this photon-phonon interaction to solve real-world problems. His research team based at the Sydney Nanoscience Hub and the School of Physics has produced more than 70 papers on the topic.